1. Field of the Invention
The present invention relates to an intracranial ventricular catheter assembly for studying intracranial pressure and compliance and for sampling of cerebrospinal fluid. More particularly, the invention relates to a catheter assembly including a catheter having fluid sampling ports, a balloon at the distal end of the catheter by means of which ventricular volume can be increased and decreased quickly, at will, and a pressure gauge for continuous measurement of intracranial pressure.
2. Description of the Prior Art
Heretofore intracranial ventricular catheter assemblies have been provided for monitoring pressure/volume relationships within the intracranial ventricles and for determination of intracranial pressure.
All such previously proposed catheter assemblies provided for direct fluid addition or withdrawal from the intracranial ventricular system. This type of direct fluid contact has a number of disadvantages. For one thing, direct fluid addition increases the risk of infection. Also, the infusion of a volume of fluid into the ventricles precludes intracranial pressure measurement on an uninterrupted basis. If continuous monitoring is required, then the adjustment in volume must be compensated for via a second access site for withdrawal of added fluid, again increasing the risk of infection or tissue injury. Further, by the direct infusion of fluid, the intracranial pressure may also be caused to rise precipitously, even without a beginning elevated baseline, requiring that the infused fluid be immediately removed. In some instances, immediate removal of the infused fluid is not possible, the fluid having become "trapped" within the ventricular space. Consequently, the intracranial pressure may remain elevated for too long a duration while attempts to bring it down by other means are being undertaken.
The catheter assembly of the present invention overcomes many of these disadvantages by providing (1) safe, reliable means for increasing the intracranial volume with no direct contact of infused fluid and cerebrospinal fluid; (2) means for immediate removal of the infused fluid, if necessary; and (3) means for monitoring intracranial pressure simultaneously during pressure/volume change testing, as will be described in greater detail hereinafter.